|Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
|Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
|Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential.
|Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
|Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
|Likelihood of Avalanches
|Natural and human-triggered avalanches unlikely.
|Natural avalanches unlikely; human-triggered avalanches possible.
|Natural avalanches possible; human-triggered avalanches likely.
|Natural avalanches likely; human-triggered avalanches very likely.
|Natural and human-triggered avalanches certain.
|Avalanche Size and Distribution
|Small avalanches in isolated areas or extreme terrain.
|Small avalanches in specific areas; or large avalanches in isolated areas.
|Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.
|Large avalanches in many areas; or very large avalanches in specific areas.
|Very large avalanches in many areas.
Another round of snow is expected to come in fast and furious today. Winds, combined with high snowfall rates will rapidly load slopes and quickly increase avalanche danger. If the forecast verifies, instability will be on the rise for all the classic storm snow avalanche concerns:
Winds out of the East are currently increasing. With ample snow available for transport, naturally occurring wind slab avalanches 1-3′ thick are possible on leeward slopes and rollovers, also watch for cross-loading in gullies. I’d expect much of today’s avalanche activity to be in the form of wind slabs of varying thickness.
Snowfall today will be falling on low density powder from Sunday night. Though today’s snow is expected to be low density as well and not prime conditions for creating storm slabs, the simple “rapid loading” that is expected has the potential to do this – even without the presence of wind. These slabs will be soft and could occur naturally on steep slopes at all elevations.
Loose Snow avalanches:
Loose snow sluffs should be expected. The biggest concern with these is the possibility for initiating either a storm slab or a persistent slab on the descent.
Today will be ideal cornice growth and calving conditions. The main concern with cornices also has to do with the possibility for triggering a larger slab below.
*Note: The AKDOT webcam is working again on Turnagain Pass! Keep tabs on snowfall as well as the road conditions with this link.
Today we will be adding yet another load to our tenuous snowpack and potentially overloading the weak snow that sits just above the thick January crust. This weak layer of faceted snow has been well documented over the past two weeks and sits below all the February storm snow – between 2 and 3 feet deep. These persistent slab avalanches have the ability to propagate over entire slopes and be around 2-3′ deep (deeper with any additional snow).
In the event the storm today does not produce, this avalanche problem will be the primary concern. We have already seen multiple large remotely triggered slides occur in this mid-pack weak layer and today will be no different.
|Avalanche: Base of Seattle Ridge
|Troy Tempel, Thomas Lees, .Josh Bollaert, Damian Naquin
|Observation: Lynx creek
|Observation: Tincan Trees
|Moderow / Clayton
|Observation: Turnagain (below the uptrack)
|Alaska Avalanche School Moto Level 2
|John Sykes Forecaster
|Observation: Tincan Backdoor, Center Ridge
|AAS Level 1 / R Sullivan
|Avalanche: Tincan Trees
|Schauer/ Moderow/ Stephenson Forecaster
|Schauer/ Moderow/ Clayton Forecaster